4 Answers
4

Class specific weapons can provide some class only enchantments that you cannot get on standard weapons. Whether or not this is worth a trade off for damage, that is entirely up to you to decide.

For instance, you can find a demon hunter only 1 handed crossbow that provides hatred regeneration or a wand for mages that provides improved arcane pool.

Like James mentioned in his answer, the demon hunter is the only class that has a unique situation where you MUST have a ranged weapon equipped or you can't use his ranged attack skills. And his one handed crossbow is the only ranged weapon you can dual wield.

From my own experience (read below), as long as you can use the weapon and it has better stats, it will increase the effectiveness of your characters abilities which are all weapon damage based.

However, as I approached level 10 or so I started finding versions of weapons that could only be used by their respective classes. This was most notable with bows/crossbows that could only be wielded by a demon hunter. Also some 2h weapons that I believe were either for the barbarian (Hammer) or monk (Daibo) sort of deal.

I cannot say for sure for another couple of weeks as they had us pretty limited in the open beta this weekend, but I do look forward to getting more information in this area. I played up to level 7 using my noob wand on a Wizard until it was pointed out that I can use just about any weapon and my skills will still work. NOTE: This did not work for the Demon Hunter actually. Using a melee weapon stopped most 'shooting' base skills from working.

Class-specific items do not have any intrinsic benefits, other than the ability to spawn with class-specific affixes, as yx mentions.

On a pure stats basis, I do not believe class-specific items are any better either. In every category I checked, class-specific weapons had equal or lower DPS than the class-neutral variant, and the same number of possible magic affixes.

Of course this does not affect set or legendary items. But what it comes down to is, use the item with the best stats and bonuses present (as long as you like its attack speed), regardless of item type.

Given two weapons in your inventory that are otherwise identical, there is no advantage to picking a class-specific weapon over a general weapon. A class-specific weapon may have stats that are impossible to find on a general weapon, so in some cases, you may prefer it because the class-specific weapon happens to be better.

It's also worth noting that class-specific weapons are often cheaper on the auction house than the more general weapons (assuming the same stats on both). For that reason, I like to equip class-specific weapons and sell the more flexible weapons.

All that does not mean that all weapons are identical for each class. Several classes, in particular, Demon Hunters, Witch Doctors, and Wizards, have channeling spells. A channeling spell uses your resource (Hatred, Mana, or Arcane Power respectively) with each attack. For those spells, slower weapons are better (assuming that you are comparing two weapons with the same damage per second). The fewer attacks per second, the less resource you use. Two-handed weapons are often slower than one-handed weapons, so there are spell-caster builds that favor them.

Demon Hunters have abilities that require ranged weapons to use. If you want to use those abilities, you need to equip one of a bow, a crossbow, or a hand crossbow. Demon Hunters can also use quivers with two-handed weapons like a bow or crossbow as well as with the one-handed hand crossbow. Combining minimal resource use with maximal choice of abilities means that Demon Hunters favor crossbows with a quiver.

A Wizard also has an alternative build called the Critical Mass/Windup Wizard. This build relies on getting as many critical hits as possible. For that reason, you want to maximize attack speed (as well as critical hit chance). The dagger is the fastest weapon that a Wizard can use, so it is optimal for that build. Wands are slower and less suited to that build. However, if attack speed is already high enough, Wizards often choose to use a wand to gain class-specific abilities like Arcane power on critical hits.

A Barbarian has a number of options. They can use a two-handed weapon, dual-wield, or use a shield. In hardcore, shields with a one-handed weapon are most common (defense first). In softcore, Barbarians favor dual-wielding. Barbarians tend to prefer faster weapons which generate Fury quickly to keep their Wrath of the Berserker running.